76244-New-generation accelerators such as the Linac Coherent Light Source at SLAC will require new, high-performance laser-driven photoinjectors. This will require a substantial advance in the state-of-the-art for ultrafast laser technology, in order to obtain the required pulse energy, shape and duration, and average power. In this project, a laser system will be designed and constructed to provide light pulses of 10 psec duration (0.5 psec rise/fall) and greater than 25 mJ pulse energy at 800 nm and 120 Hz, for generation of UV pulses to drive the photoinjector. Phase I will upgrade existing design codes in order to: (1) simulate the generation, propagation, and frequency upconversion of a pulse with the required temporal shape; and (2) study thermal loading in the various laser amplifiers. If feasible, proof-of-principle experiments will be conducted to verify pulse-shaping issues. A suitable overall laser design will be developed, with implementation in Phase II to allow for a study of pulse-shape, beam quality, and pulse stability issues. Commercial Applications and Other Benefits as described by the awardee: The technology should be useful for a variety of applications in both research and industry, including photoinjectors for various accelerators and large-scale light sources, research in ultrafast materials dynamics, and precision micromachining.